Coal processing

ABSTRACT

A METHOD FOR HYDROGENATING COAL TO AT LEAST PARTIALLY LIQUIFY SAME WHEREIN THE HYDROGENATION IS CARRIED OUT IN AT LEAST ONE ZONE CONTAINING AN EBULLATED BED OF SUBSTANTIALLY INERT, SOLID CONTACT PARTICLES.

May 2, 1972 i v ETAL 3,660,267

COAL PROCESSING Filed OCL. 14, 1970 GAS LIQUID,COAL, Z ASH SOLVENTSOLiDS PURGE INVENTOR ROBERT W R/EVE HAROLD .SHAL/T ATTORNEY UnitedStates Patent 3,660,267 COAL PROCESSING Robert W. Rieve, Springfield,and Harold Shalit, Drexel Hill, Pa., assignors to Atlantic RichfieldCompany, New York, NY.

Filed Oct. 14, 1970, Ser. No. 80,662 Int. Cl. Cg 1/04 US. Cl. 208-8 7Claims ABSTRACT OF THE DISCLOSURE A method for hydrogenating coal to atleast partially liquify same wherein the hydrogenation is carried out inat least one zone containing an ebullated bed of substan tially inert,solid contact particles.

BACKGROUND OF THE INVENTION Heretofore it has been taught thatsubdivided, solid coal can be gasified and liquified by hydrogenation inan ebullated bed of externally supplied hydrogenation catalyst such as acobalt molybdate catalyst. Such a process is fully and completelydisclosed in US. Pat. Re. 25,770, the disclosure of which isincorporated herein by reference.

In conducting these catalytic processes the temperature of the reactionwas generally kept in the range of 825 to 900 F. to avoid unduepyrolysis of the coal, or coal products as evidenced by substantiallyincreased gas production from the reaction zone.

SUMMARY OF THE INVENTION It has now been found that the hydrogenation ofcoal to substantially gasify and liquify same can 'be carried out in theabsence of an externally supplied hydrogenation catalyst when using anebullated bed of substantially solid contact particles composed of amaterial which is substantially inert and non-catalytic as to thehydrogenation reaction.

It has additionally been discovered that by utilizing these inert andnon-catalytic contact particles in lieu of catalytic particles,temperatures in excess of 900 F. and up to 1000" F. can be employedwithout undue pyrolysis as evidenced by increased gas production.

It has additionally been discovered that when employing a reactiontemperature of from about 850 to about 1000 F. and a coal feed rate offrom about to about 200 pounds of coal per hour per cubic foot ofreactor, substantially the same product distribution can be achieved asif the reaction was carried out at a lower temperature with the use ofcatalytic particles and with less hydrogen consumption than thecatalytic reaction.

Thus, this invention is useful in converting normally solid coal orsimilar carbonaceous materials to liquid hydrocarbonaceous productswhich are useful in producing gasoline, fuel oil, and the like.

Accordingly, it is an object of this invention to provide a new andimproved method for carrying out a coal hydrogenation process. It isanother object to provide a new and improved process whereby anon-catalytic reaction can be substituted for a catalytic reactionwithout sacrifice in the product distribution of the reaction. It isanother object to provide a new and improved method for employing anon-catalytic coal hydrogenation process wherein the hydrogenconsumption is decreased without sacrifice in the product distributionnormally achieved by the catalytic process. It is another object toprovide a new and improved process for the hydrogenation of coal whereinthe reaction temperature of the process can vary over 0 a wider rangethan that of the catalytic process without 7 experiencing unduepyrolysis of the coal.

3,666,267 Patented May 2, 1972 'ice DETAILED DESCRIPTION OF THEINVENTION The drawing shows a diagrammatic representation of anapparatus useful in practicing this invention.

More specifically, the drawing shows a conventional ebullated bedreactor 1 which contains no hydrogenation catalyst 'but rather containsonly a bed of particular material 2 which is substantially inert andnon-catalytic as to the hydrogenation reaction. Thus, no subdividedcatalytic material is supplied to reactor 1.

What is supplied to reactor 1 is comminuted coal by way of pipe 3 andhydrocarbonaceous slurry medium (solvent) by way of pipe 4 to form acoal slurry which is passed by way of pipe 5 after being heated byheater 6 into a lower portion of reactor 1. The mixture passes upwardlythrough perforate screen 7 and bed 2 to etlluent pipe 8. Hydrogen and/orhydrogen-donating liquid and/ or hydrogen-donating gas is supplied byway of pipe 13.

The overhead effluent from reactor 1 is passed by way of pipe 8 to aconventional separation system 9 which can include fractionators,cyclones, strippers, and the like and which separates a gaseoushydrocarbonaceous product by'way of pipe 10 and a substantially liquidhydrocarbonaceous product by way of pipe 11. The hydrocarbonaceousliquid product also contains certain solid residual matter such asunconverted coal, char, coke, and ash. This product can be taken 'by wayof pipe 12 for further treatment whereby the unconverted coal, etc. areseparated from the liquid and the liquid fractionated into variousgrades of products such as resid, kerosine, and the like.

Part or all of the product in pipe 11 can be returned by way of pipe 14to pipe 5 whereby it re-enters reactor 1 for retreatment.

In the operation of reactor 1 in accordance with this invention, reactor1 can be initially started up with the contact particles alreadytherein. These contact particles can be subdivided refractory and/ orinert materials such as sand, alpha-alumina, quartz, pumice, glassbeads, silicon carbide, mullite, and the like.

Pipe 15 is employed above screen 7 so that solids can be removed fromthe bed as desired. Also, if desired, solids can be added to reactor 1by way of pipe 15.

If desired, more than one reactor 1 can be employed in parallel and/orseries and still be within this invention. The operation of one reactoris fully and completely disclosed here only for sake of brevity.

Reactor 1 is, therefore, operated so that amounts of coal slurry,hydrogen, and the like added to bed 2 and the velocities of thesematerials is adjusted in a manner known in the art so as to provide andmaintain an ebullated bed 2, the distinction here being that theebullated bed is composed of a plurality of contact particles that aresubstantially non-catalytic as regards the hydrogenation reaction takingplace in reactor 1.

The inert contact particles are subdivided and are preferably in thesize range of from about plus 200 mesh (Tyler) to about inch in largestcross-sectional dimension. The amount of inert, non-catalytic particlesempolyed in bed 2 can vary widely but generally will be from about 5 toabout percent by weight.

If desired, there can be added to reactor 1 water in the amount fromabout 0.1 to about 50 weight percent based on the total weight of thecoal being added to reactor 1. If water is added it can be injected intoany one or more of reactor 1, pipes 3, 4, 5, 14, and the like, and/or byaccompanying the coal which is being fed into pipe 3. The water can beadded in the form of cool, ambient, or heated liquid water and/or steam.If part of the water supplied is that which accompanies the raw coalfeed to pipe 3, this water can be that which accompanies the coal fromthe mine or can be added during comminuation of the coal, and the like.

It should be noted a distinct advantage for this invention is that wetcoal can be charged to the hydrogenation reactor without fear ofdisrupting the hydrogenation reaction. This is not always so when ahydrogenation catalyst is employed. For example, water is a deactivatingpoison to some catalysts, such as platinum or alumina, and the use ofwet coal would be avoided when such catalysts are present. Accordingly,in the practice of this invention coal drying is eliminated since wetcoal can be used with impunity.

Substantially any coal can be employed in this invention. For example,semi-anthracite, bituminous, semibituminous, sub-bituminous, lignite,peat, and the like can be used.

The slurrying medium in pipe 4 can be a liquid hydrocarbonaceousmaterial produced by reactor 1 and/or a hydrogen-donor liquid such astetralin or partially hydrogenated 3 or 4 ring aromatics such asanthracene, naphthalene, phenanthrene, and the like. Other hydrogendonormediums may be obtained by hydrogenation of the hydrocarbonaceous liquidproducts of reactor 1. Such a medium would boil within the range of fromabout 400 to about 950 The hydrogen-donor liquids are optional from ahydrogenation standpoint because adequate hydrogenation can be obtainedwith molecular hydrogen from pipe l3,alone.

The coal should be comminuted and can have a maximum particle size ofabout minus 8 mesh (Tyler). The comminuted coal is mixed with the slurrymedium to form the coal slurry charged to reactor 1. The coal slurrypreferably has a solvent/coal weight ratio as added to reactor 1 of fromabout 0.1 to about 4. The solventpart of the coal slurry can be formedcompletely or partially from externally added solvent from pipe 3 orhydrocarbonaceous liquid products from pipe 14 or combinations of thetwo as desired.

Molecular hydrogen and/or hydrogen containing gas can be charged by wayof pipe 13 in an amount such that the hydrogen partial pressure inreactor 1 is maintained at from about 400 to about 3000 p.s.i.a.

Reactor 1 should be operated at a temperature of at least about 850 F.and a total pressure of from about 400 to about 5000 p.s.i.g. The totalliquid and gas passing into reactor 1 should be in an amount and at avelocity sufficient to cause the solid particles present in bed 2 tobecome an ebullated bed, i.e., so that the solids are in an expandedstate and occupy at least 10 percent greater volume than the settledvolume of the particle mass of bed 2 and additionally are in randommotion in the gas-liquid system. In an ebullated bed there is a sharpand finite level of the solid particles of the solid inert,non-catalytic particles, below which the solid particles exist at aconcentration in excess of pounds per cubic foot of reactor space andabove which the solid particles exist at a concentration less than 0.1pound per cubic foot of reactor space.

It is preferable in order to practice a preferred embodiment of thisinvention and to obtain a product distribution in pipe 18 approximatingthat of a catalytic reaction to operate reactor 1 in a temperature rangeof from about 850 to about 1000 F. using a coal addition rate of fromabout 15 to about 200 pounds of coal per hour per cubic foot of reactor.By keeping within these ranges with an inert particle ebullated bed, notonly is catalyst cost saved but there is no sacrifice in productdistribution and this is accomplished with a decrease in hydrogenconsumption. Further, the reaction can be operated at a temperature upto 1000 F. without encountering undue pyrolysis as evidenced byincreased gas production.

Being able to operate at a higher temperature without undue pyrolysishas the advantage of allowing a higher throughput of material forreactor 1 thereby, for a given set of reaction conditions, increasingthe product output of reactor 1. Alternatively, one can keep the samethroughput for a given set of reaction conditions but use a smallervolume reactor.

EXAMPLE I A Pittsburgh No. 8 coal comminuted to percent through a No. 40U .S. Sieve particle size range was mixed with a solvent composed ofcoal derived oil having a 350 to 850 F. boiling range in a solvent/ coaladdition weight ratio of 4/ 1 and subjected to hydrogenation withmolecular hydrogen using a coal addition rate of 31.2 pounds of coal perhour per cubic foot of reactor and a reaction time of 0.38 hour. One runwas carried out at 825 F. using cobalt molybdate catalyst as the solidparticles in the ebullated bed, the catalyst particles being in the inchcylindrical extrudate size. One run was carried out at 850 F. usingtabular alumina as the solid particles in the ebullated bed, the inertparticles passing through a No. 8 and being retained on a No. 12 U.S.Sieve.

The results of the runs were as follows:

Catalytrc Inert bed CO and 002* 0.3 0.5 Methane through propane* 4. 5 4.4 Butane and heavier benzene soluble liquid 67. 5 66. 6 Benzeneinsoluble liquid product 11.5 12. 3 H1 consumption 4. 8 1.0 Unconvertedcoal 6.2 5. 9

* Weight percent based on MAF coal.

EXAMPLE II A Pittsburgh No. 8 coal comminuted to 100 percent passthrough a No. 40 U.S. Sieve was mixed with a solvent composed of a coalderived oil having a 350 to 850 F. boiling range in a solvent/coaladdition weight ratio of 4/1 and subjected to hydrogenation withmolecular hydrogen using a coal addition rate of 93.7 pounds of coal perhour per cubic foot of reactor and a reaction time of 0.12 hour. Tworuns were carried out at 850 F. and 893 F. using cobalt molybdatecatalyst, in the V inch cylindrical extrudate size, as the solidparticles in the ebullated bed. Two additional runs were carried out at850 F. and 893 F. using tabular alumina, having a particle size passingthrough a No. 8 and retained on a No. 12 U.S. Sieve, as the solidparticles in the ebullated bed.

The results of the runs were as follows:

Weight percent based on MAF coal.

It can be seen from the above data that the inert bed run at 893 F. hadessentially the same product distribution as the catalytic bed run at850 F. but that the hydrogen consumption was substantially reduced.

Reasonable variations and modifications are possible within the scope ofthis disclosure without departing from the spirit and scope of thisinvention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In the hydrogenation of coal wherein a mixture of subdivided coal anda hydrocarbonaceous solvent is subjected to hydrogenation conditions offrom about 850 to about 1000 F. and from about 400 to about 5000p.s.i.g. in at least one hydrogenation zone, the improvement comprisingsaid zone containing an ebullated bed of substantially solid contactparticles, operating said at least one hydrogenation zone in the absenceof externally supplied hydrogenation catalyst, and employing as saidcontact particles a material which is not derived from coal and which issubstantially inert and non-catalytic as to the hydrogenation reaction.

2. A process according to claim 1 wherein said particles are composed ofsand, alumina, quartz, pumice, glass beads, silicon carbide, andmullite.

3. A process according to claim 1 wherein said particles are in the sizerange of from about plus 200 mesh to about inch.

4. A process according to claim 1 wherein said hydrogenation conditionsinclude a solvent/coal addition weight ratio of from about 0.1 to about4 and a hydrogen addition rate sufficient to maintain a hydrogen partialpressure of from about 400 to about 3000 p.s.i.a.

5. A process according to claim 1 wherein said particles are present insaid bed in the range of from about 5 to about percent by weight.

6. A process according to claim 1 wherein said solvent boils in therange of from about 400 to about 950 F. and is at least one of ahydrogen-donor hydrocarbonaceous liquid and a hydrocarbonaceous oilderived from a coal and/or oil hydrogenation process.

7. A process according to claim 1 wherein said hydrogenation is carriedout in the coal addition range of from about 15 to about 200 pounds ofcoal per hour per cubic foot of reactor.

References Cited UNITED STATES PATENTS 1,702,899 2/ 1929 Howard 208-81,704,792 3/1929 Debo 208-8 Re. 25,770 4/ 1965 Iohanson 20810 3,536,60810/1970 Riedl 208-10 DELBERT E. GANTZ, Primary Examiner V. OKEEFE,Assistant Examiner

